JP3392822B2 - Sheet-fed rotary printing press having a printing unit for multicolor printing and at least one coating unit - Google Patents

Abstract

The press has at least one coating unit. Each coating unit has a sheet guide cylinder, a form cylinder and a dosing system with application roll (3). Each coating unit (13, 14), fitted after the printers (12) in the feed direction, has a cleaning doctor system which can be pressed against and withdrawn from the application roll. This system is fitted in front of the dosing system in the turning direction of the roll.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a sheet-fed rotary printing press having a printing unit for multicolor printing and at least one coating unit as defined in the preamble of the main claim.

[0002]

2. Description of the Related Art A rotary printing machine of the same type is disclosed in European Patent No. 0620 11.
It is well known from Japanese Patent Publication No. 5. At least two coating units are provided as coating units for coating sheet-like printing materials in-line. The coating unit provided on the front side in the sheet running direction is provided with a relief printing plate, a plate cylinder that is in contact with an impression cylinder that conveys the sheet, and an inking (coating) that is in contact with the plate cylinder. Formed as a flexographic printing device having an abuttable chamber doctor connected to an inking roller provided with a grid for supplying a supply pump for supplying the coating liquid and a suction pump for backflowing the coating liquid. ing.

From DE 195 26 574 A1 is known a method and a device for cleaning a plate cylinder (with a printing plate) and an inking roller. This method and apparatus reduces the fast drying solvent that adheres to the inking roller and plate cylinder upon drying. The cleaning device has two curved surfaces, which are directed towards the inking roller and the plate cylinder.

A chamber doctor as a dosing mechanism is known from US Pat. No. 5,121,689. Here, the working doctor is connected to the ultrasonic device and dispenses the layer thickness of the printing ink provided on the dispensing roller.

DE 196 45 934 A1 describes an inking roller with a grid. The recesses of this roller are filled with a liquefiable substance as a gravure printing plate and can be regenerated using an ultrasonic cleaning device up to the basic grid shape of the recesses.

DE 41 21 017 describes a cleaning device with a roller coated with a soft, smooth rubber and a scraping roller with a corresponding polygonal cross section. An ultrasonic cleaning device is provided to remove the printing ink from the circumferential surface of the scraping roller.

Sheet-fed rotary printing presses having a printing unit for multi-color printing and at least one coating unit, ie a flexographic printing device and / or a coating device, for example, have the potential for the coating liquid to become contaminated and thus the printing quality. Has the disadvantage of being damaged. If this happens, the quality of one sheet of paper will vary even during the coating process.

[0008]

The object of the invention is to prevent the abovementioned disadvantages, in particular to ensure a stable quality during the coating process and to significantly reduce the contamination of the coating liquid. It is to provide a sheet-fed rotary printing press.

[0009]

These problems are solved by the structural features of the main claim. Further formations are described in the dependent claims.

A first advantage is that in a metering mechanism, which is preferably formed by a chamber doctor and an inking roller provided with a corresponding grid, the inking roller is continuously or discontinuously cleaned of dirt. Is. Alternatively, a flat-surfaced inking roller can be used in the dosing mechanism instead of a gridded (recessed and bridged) inking roller.

A further advantage is that the printing material is especially
Ink backflow divergence (flexo and / or offset printing inks of the preceding printing process) to the metering mechanism of the coating unit is prevented. Such a backflow branch of ink occurs from a printing process in a printing device provided in the front in the transport direction. If, for example, the chamber doctor is used with an inking roller provided with a grid, the possibility of residual ink depositing on the chamber doctor and / or the inking roller and with it mixing with the coating liquid is prevented. If a device with two rollers (according to the principle of a squeezing roller with a commonly formed roller gap) is used, the roller gap formed by the dosing roller and the inking roller and / or the inking roller Accumulation of residual ink is prevented. This point also applies to the metering mechanism based on the principle of the scooping roller. Such a metering mechanism prevents contamination of the collection container, the roller train and / or the inking roller.

A further advantage is that the number of wash intervals for each dosing mechanism with the inking roller can be reduced.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail according to the embodiments.

The printing machine comprises a plurality of printing devices 12 for multi-color printing, preferably offset printing devices, arranged in a row, the first coating unit in the conveying direction 5 of the sheet-shaped printing material. 13 and a second coating unit 14 are provided behind the printing device 12. A drying unit 15 is preferably provided between the coating units 13 and 14. A delivery device 19 is provided behind the second coating unit 14,
The delivery device is formed in particular by a circulating transport mechanism 21, which deposits the sheets on the delivery device stack 22. The present invention can also be used when the coating units 13 and 14 are stacked.

The printing device 12 mainly comprises a plate cylinder 16 and a transfer cylinder 17.
And a sheet transport cylinder 1 which is an impression cylinder. The plate cylinder 16 is provided with an inking device and optionally a dampening device adjacent to the plate cylinder 16. The dampening device will not be described in detail here.

Between the printing device 12, the coating units 13 and 14, and the drying unit 15, a sheet transporting cylinder 18 is provided as a private cylinder for transporting the sheet-shaped printing material. Sheet transport cylinder 1,18
Is twice as large as the transfer cylinder 17 or the plate cylinder 2 is 1.

The first coating unit 13 is formed as a coating device for processing with a dispersion varnish containing a pigment of an aqueous base, for example, the sheet conveying cylinder 1 (impression cylinder),
Plate cylinder 2 capable of contacting a sheet conveying cylinder 1 having a relief printing plate having flexibility as a coating plate, and a first metering mechanism 20.
Composed of. The first metering mechanism 20 is formed by a grid-forming (having recesses and bridges) inking roller 3 abuttable on the plate cylinder 2 and a chamber doctor 4 operatively connected to this inking roller 3. ing.

The second coating unit 14 is also formed, for example, as a coating device for treating with a dispersion varnish of an aqueous base, and also the sheet conveying cylinder 1 (impression cylinder) and the sheet conveying cylinder having a rubber blanket. It is composed of a plate cylinder 2 capable of abutting on 1 and a second metering mechanism 20. The second metering mechanism 20 is formed by an inking roller 3 and a metering roller 23, which have a preferably smooth surface, and which can contact the plate cylinder 2, and a common roller gap.

Each metering mechanism 20 has a piping mechanism having a supply pipe 10 and a backflow pipe 11 for circulating a liquid coating agent or a cleaning liquid. In this piping mechanism, the supply pipe 10 and the backflow pipe 11 communicate with the inside of the metering mechanism 20. In the chamber doctor 4, it is the chamber that is operatively connected to the inking roller 3.
In a device having two rollers (principle of a squeezing roller), the supply pipe 10 communicates above a commonly formed roller gap, and the backflow pipe 11 is guided to the end face side of the roller gap. As another method, a metering mechanism 20 based on the principle of a scooping roller
Then, the supply pipe 10 communicates with a scooping roller or a container,
The backflow pipe 11 is guided from the container.

In the coating units 13 and 14, a gap is formed between each inking roller 3 and each plate cylinder 2. The inking roller 3 and the plate cylinder 2 can contact or separate from each other.

The coating units 13 and 14 provided at the rear of the printing device 12 are respectively provided so as to be able to contact or separate from the corresponding inking roller 3 and have a cleaning doctor mechanism 8 extending over the width of the roller. Then, in the cleaning doctor mechanism, in the gap 6 (contact position between the plate cylinder 2 and the inking roller 3), the respective dosing mechanisms 20 (chamber doctor 4, dosing roller 23) in the rotation direction 7 of the corresponding inking roller 3. It is provided in front of.
The cleaning doctor mechanism 8 has a closing doctor and a working doctor which are each operatively connected to the inking roller 3. The closing doctor and the working doctor have side sealing members and are detachably mounted in a casing forming a chamber.

The cleaning doctor mechanism 8 preferably has an ultrasonic oscillating mechanism 9, and the oscillation of the ultrasonic oscillating mechanism is directed directly to the roller surface of the inking roller 3. The ultrasonic oscillating mechanism 9 is preferably fixed to the casing of the cleaning doctor mechanism 8. The cleaning doctor mechanism 8 is also connected to a supply pipe 24 or a backflow pipe 25 which communicates with the inside of the chamber or branches from the chamber for circulating a cleaning liquid such as water. Such circulation takes place via a controllable pump mechanism.

The ultrasonic oscillating mechanism 9 can be operated or stopped during the coating process (the metering mechanism 20 is operating),
It is mechanically linked to the machine control. The cleaning doctor mechanism 8 can be brought into or out of contact with the inking roller 3 during the coating process, for example by means of a rotary joint and a working cylinder. In the contact state, the cleaning liquid can be supplied via the supply mechanism 24 or the backflow mechanism 25. Then, if necessary, the ultrasonic oscillating mechanism 9 is activated. In the case of the inking roller 3 having a smooth surface, the doctor blade and the feeding and backflow mechanism 2
A cleaning doctor mechanism 8 with 4, 25 can be used. When the inking roller 3 provided with a grid is used, the cleaning mechanism 8 having a further ultrasonic oscillating mechanism 9 is preferably used.

In the embodiment according to FIG. 2, the cleaning doctor mechanism 8 is arranged on the inking roller 3 facing the metering mechanism 20, in the figure the chamber doctor 4, and has a closing and working doctor.

In FIG. 3, the cleaning doctor mechanism 8 is the metering mechanism 2
0, it is built in the chamber doctor 4 in the figure, but it is provided in front of the chamber doctor 4 in the rotating direction. The advantage in this case is that only one doctor blade is required to separate the chamber from the chamber doctor 4 and the cleaning doctor mechanism 8 and thus an additional doctor blade is omitted.

In FIG. 4, the cleaning doctor mechanism 8 is also formed with a closing and working doctor, but is provided on the same side as the chamber doctor 4 with respect to the inking roller 3 and in front of the chamber doctor in the direction of rotation. Has been. In this case, the chamber doctor 4 is in direct contact with the cleaning doctor mechanism 8. On the other hand, in FIG. 5, the chamber doctor 4 and the cleaning doctor mechanism 8 provided on the same side of the inking roller 3 are spatially separated.

During the coating process, if an ink backflow branch occurs on the inking roller 3 (possibly the metering roller 20) of the first or second coating unit 13, 14 and optionally further coating units, respectively. The cleaning doctor mechanism 8 is activated. The cleaning liquid circulated by the supply mechanism 24 and the backflow mechanism 25 contacts the surface of the inking roller 3, and the ink is etched and separated. Depending on the degree of dirt or the type of surface of the inking roller 3, the ultrasonic oscillating mechanism 9 is operated to further enhance the cleaning effect. In that case, the washing step is carried out continuously or discontinuously.

In order to prevent the rest of the cleaning liquid from entering the metering mechanism 20, inside the cleaning doctor mechanism 8 for the purpose of drying the inking roller 3 by means of air supply, for example of a blower pipe extending over the width of the roller. Such a blower can be provided. Alternatively, such an air blower may be provided between the cleaning doctor mechanism 8 and the metering mechanism 20, for example, the chamber doctor 4. In a further configuration, the cleaning doctor mechanism 8 has at least one cleaning brush inside for supporting the cleaning effect.

To form the metering mechanism 20 with the chamber doctor 4 and the inking roller 3 with a grid, in one formation the chamber doctor 4 is provided with an ultrasonic oscillating mechanism 9. Such an arrangement is preferably configured similarly to the cleaning doctor mechanism 8 provided with the ultrasonic oscillating mechanism 9. An advantage of configuring the chamber doctor 4 provided with the ultrasonic wave oscillating mechanism is that the ultrasonic wave oscillates continuously or discontinuously on the coating agent inside the chamber doctor 4. As a result, in particular, the fine air bubbles generated by the air carried into the chamber doctor 4 from the empty recesses of the inking roller 3 provided with the grid can be collected very well. Larger gas bubbles formed in this way can preferably be led out from inside the chamber doctor 4. Before that, the larger gas bubbles float faster inside the chamber doctor 4 than the fine bubbles. By removing the gas bubbles, the coating process is further supported and the quality becomes more stable.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a sheet-fed rotary printing press for multicolor printing having two coating units.

FIG. 2 is a schematic side view of essential parts showing an embodiment of a coating unit according to the present invention.

FIG. 3 is a schematic side view of essential parts showing another embodiment of the coating unit according to the present invention.

FIG. 4 is a schematic side view of essential parts showing another embodiment of the coating unit according to the present invention.

FIG. 5 is a schematic side view of essential parts showing still another embodiment of the coating unit according to the present invention.

[Explanation of symbols]

1 impression cylinder 2 plate body 3 Inking roller 4 chamber doctor 5 Transport direction 6 gap 7 rotation direction 8 Cleaning doctor mechanism 9 Ultrasonic swing mechanism 10 supply pipes 11 Backflow tube 12 Printing device 13 Coating unit 14 Coating unit 15 Drying unit 16 plate body 17 Transfer cylinder 18 my torso 19 Sending device 20 Distributor 21 Transport mechanism 22 Paper feeding device 23 Distributor roller 24 supply mechanism 25 Backflow mechanism

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Ulrich Jung Germany 65551 Limburg Frank Fruther Strasse 65 Ar (56) Reference JP-A-11-240136 (JP, A) JP-A-9-29948 (JP, A) US Patent 5121689 (US, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) B41F 31/08 B41F 31/20 B41F 35/04

Claims (5)

(57) [Claims] 1. A sheet-fed rotary printing press having a printing unit for multicolor printing and at least one coating unit, each coating unit comprising a sheet transport cylinder, a plate cylinder and an inking roller. The coating unit (13, 14) provided behind the printing device (12) in the conveying direction (5) has a metering mechanism and can contact and separate from the inking roller (3), respectively. It has a cleaning doctor mechanism (8) provided, said cleaning doctor mechanism being the rotating direction (7) of said inking roller (3).
At the rear of the plate cylinder and at the metering mechanism (2
0), a sheet-fed rotary printing press. 2. The cleaning doctor mechanism (8) is formed of a closed doctor, a working doctor and a lateral sealing member, and has an ultrasonic oscillating mechanism (9), and the ultrasonic oscillating mechanism of the ultrasonic oscillating mechanism. 2. The sheet-fed rotary printing press according to claim 1, characterized in that is directed directly onto the roller surface of the inking roller (3). 3. The sheet-fed rotary printing press according to claim 1, wherein the ultrasonic oscillating mechanism (9) can be activated or stopped during the coating process. 4. Sheet according to claim 1 or 2, characterized in that the cleaning doctor mechanism (8) can be operatively coupled to the inking roller (3) or released from the operative coupling during the coating process. Sheet-fed rotary printing press. 5. The supply mechanism (24) and the backflow mechanism (2) for circulating the cleaning liquid by the cleaning doctor mechanism (8).
5. A sheet-fed rotary printing press as claimed in claim 1, characterized in that it is connected to 5).